I was reading a blog post here, that states that in like 10 minutes they were able to change an old AS/400 Green Screen Application into a web interface.
But they don't really make mention of what they used to do this.
They even modernize it by putting Google Maps Javascript APIs into it. But what on earth are they using to do so?
As CodeCaster commented...
That's Profound UI screen... https://www.profoundlogic.com/profoundui/